Mr Parsons said he pulled over when he suddenly encountered a problem. Smoke started "billowing" out from the bonnet before the engine caught fire.

“I quickly got Ollie out of the car, grabbed a few things like a laptop, retreated back and called the fire brigade,” he added.

Mr Parsons, 43, said it was only by chance that he was driving the car that day as his 34-year-old wife, Virginia Palé-Parsons, was due to take their six-month-old son Xavier and four-year-old daughter Anaïs out.

“It was only because she was poorly that she didn’t do the trip, it could have quite easily been her and the children in the car,” he said.

“Trying to get them out of the car in the rush hour would have been awful.

“It didn’t take long for the fire to take hold so it could have ended up in a very different way."

James Parsons' car in flames on the M25 near Chertsey

“I was shocked but just went into autopilot, grabbed whatever I could and got to safety.

“To have it happen to you is frightening but it’s just the thought of it happening to someone else. Afterwards you have time to reflect and realise how scary it was.”

Mr Parsons said his son had been ‘traumatised’ by the incident.

“The fire quickly took hold and the car exploded not long after,” he said.

“The fire brigade said we were very lucky to get out alive.”

Mr Parsons said the car, a Ford S-Max, had only had a standard service the day before the fire and was ‘nearly new’.

“Ford have said it has never happened before so it’s quite strange,” he added.

Writing on Facebook, Mrs Palé-Parsons described the incident as an ‘absolute nightmare’.

“Smoke started coming out from the bonnet,” she added. “They pulled over, got out and grabbed a few things. James went to open bonnet and the car caught fire then pretty much exploded. They are shaken but fine thankfully.

“Keep freaking out about the thought of me being in the car with Anaïs and the baby strapped in their seats. Lucky escape to say the least.”

Mrs Palé-Parsons described the car as now being ‘just a shell’.

The charred remains of James Parsons' car following the fire on the M25 near Chertsey

Crews in three fire engines from Chertsey, Painshill and Walton stations took around 45 minutes to control the blaze, which was ‘well alight’ when they arrived at the scene at around 5.30pm.

Eyewitness Henry Bodkin drove past the incident between junctions 10 and 11 on the clockwise stretch of the motorway.

He said: “It was like an inferno.

“The vehicle looked like a people carrier - the whole front end had completely burned out when I passed.

“There was a huge tower of acrid black smoke rising into the air.”

Two lanes of the motorway were closed for around two hours while emergency services dealt with the incident and road surface treatment was carried out.